Could Toyota Engineers Have Anticipated Floor Mat Issues?

A June recall of Toyota's vehicles has sparked debate over how far engineers should go in designing for misuse of products. The recall urged Toyota to fix 154,000 vehicles to prevent problems that might occur when improper floor mats are used by owners. "The accelerator pedal can get stuck in the wide open position due to its being trapped by an unsecured or incompatible driver's floor mat," said a statement from the National Highway Traffic Safety Administration (NHTSA).

The latest recall, which involves the 2010 Lexus RX 350 and Lexus RX 450h, raises questions about the role of design engineers with its citing of "unsecured or incompatible floor mats." "Sometimes, owners use floor mats from another vehicle," Toyota spokesman Mike Michels told us. "Sometimes, they use aftermarket mats. We've even found carpet remnants stacked on the floor. The record was eight -- in that case, you couldn't even see the accelerator pedal."

The 2010 Lexus RX 350 was cited in a government recall related to floor mat problems. (Source: Toyota)

Use of unsecured floor mats can be a problem when they get caught on the accelerator pedal. It's not known if the mats caused any of Toyota's incidences of unintended acceleration that dominated the media two years ago. To prevent such problems in the future, however, Toyota has had to recall hundreds of thousands of vehicles. In some cases, the company's engineers re-shaped the bottom of the accelerator pedal to create more clearance. In others, they modified the plastic pad on the floor and even altered the vehicle floor pan to make more room.

Automotive experts told Design News that Toyota engineers might have been able to prevent the floor mat issues. Even though the mats may have been inappropriate for the Toyota and Lexus vehicles, they said, the problem involved interaction between just two components -- floor mat and pedal. As such, engineers probably could have imagined the potential failure modes, tested for them, and taken preventative measures.

"They should have been able to test for most of the conditions -- when the mats slide around, when they are mispositioned, when they are upside down, and even when the driver and passenger floor mats are swapped," Steven Eppinger, professor of engineering systems at Massachusetts Institute of Technology (MIT), said in an interview. "It's impossible to test for everything, but if you make your design more robust for the 50 things you can think of, then it's likely to be robust for the 20 things you didn't think of."

Although the number and severity of the owner complaints have not yet been made public, some observers believe that use of aftermarket floor mats by American consumers may have posed an unforeseen problem for Japanese designers. David Champion, senior director of Consumer Reports Automotive Test Center, told us:

They don't consider aftermarket floor mats, especially in Japan where everything is neat and tidy. There were also other issues -- like people putting rubber floor mats on top of existing floor mats. These are forms of misuse that can happen. And any misuse that would be considered normal in the US car market should have been taken into consideration.

I own a Camery, Prius, and Venza. Of the three, the floormat on the Venza has been the only one to interfear with the gas pedal. I've had all 3 floormats fixed to prevent future problems.

Toyota seems to have only addressed the movable floormat problem, which is a simple rework. The root of the problem is that the gas pedal mechanism is in a place that it can easily jam with anything on the floor (loose papers, rags, empty beer cans, etc.). Many other cars place the mechanism above the pedal, so nothing on the floor can get stuck in it.

I haven't looked at any new Toyotas, but I hope they redesigned the pedal mechanisms and moved it from near the floor to above to prevent this type of problem in the future.

Actually, IF I was going to quote you, I WOULD say, "IGNORANCE of the Law is no excuse", since that is an exact translation of the Latin phrase to which you refer. In the days of the Roman Empire, "automobiles" were in their primitive stage of development. The Romans called them "chariots", propelled mostly by animal horsepower.......

To an earlier blogger: to those who use the argument that "when we were young, we did it this way.....", I would suggest that these very people who were once young, later grew to adulthood, and having achieved such status, became responsible for policy put into effect in one way or another, whether social, legal, or technical. So, in essence, when you now see something that you deem to be deficient for whatever reason, you have no one else to blame, except yourself, since you no dounbtedly helped whether actively or passively in creating the situation as it presently exists.

Yes, yes, yes. Toyota engineer's had an FMEA. Let's have a copy so we can see what FMEM action they had for this severity = 10 failure mode.

The obviously one is that the powertrain control module should look at both the pedal position AND the brake switch (or brake position sensor). If the brake position sensor is on, then ensure that the vehicle speed is decelerating. If not, reduce engine power until it does.

I have a 2009 RAV4, and have been involved with "accidental acceleration" at least four times now. It has happened to my wife twice, and my sister-in-law, who has the same car. We have all been driving for fifty years each, and this problem has NEVER occurred with any other vehicle. Our original-equipment floor mats have always been properly anchored.

The gas pedal and brake are EXTREMELY close together and at almost the same height. The seating position tends to right-bias the foot. When we swing our foot over to touch the brake, we remain on the accelerator, and the car lurches forward.

Newer Toyotas have firmware which reduces power to the engine when both pedals are depressed.

I can relate to the scare, but I am not sure I would phrase it this way. A hazard concerning untidy shoe strings, perhaps?

We've been warned sternly to NOT wear loose clothing near any rotating machinery (let alone operating one). If you drive, double-knotting extra long sneaker strings is definitely not judicious enough. Do something about them before you start driving; tape them down or tuck'em away.

Here is the famous example. In 1927 modern dance creator Isadora Dundan died from strangulation by a scarf she was wearing when it got entangled by the open-spoke rear wheel. Some account attributed the death to the force with which she was hurled to the stone pavement. Didn't matter. The end result was a tragic death.

Yes, Toyota Engineers should have anticipated floor mat issues. No, Toyota is in no way reponsible for any damages caused by floor mat use.

Floor mats are popular after-market products and it can be assumed that the end user will purchase a mat, just as a computer company can assume that their monitor will be used with a different video card. I mention the monitor because older monitors would self-destruct if they were attached to a video card that scanned at a higher frequency than the monitor could handle. The computer company was in no way responsible for the damage caused by the customer using an after-market video card, but the company should suffer from the ill effects of bad publicity because their poor design did not anticipate a popular upgrade to their product

I drive a 1985 Toyota truck, mainly to the commuter van pickup point; the pedals are probably much closer to each other than larger trucks.

A few years ago, I was wearing sneakers while driving my truck. I was driving on the interstate instead of the usual around-town trips in our small town. When I exited the interstate and headed down the ramp, I lifted my foot off the accelerator to apply it to the brake; meanwhile my left foot was probably automatically headed for the clutch because I like to downshift when slowing down. I had tied my sneakers with large loops on the strings.

The loop on the left side of my right foot snagged on the underside of the brake pedal, preventing me from applying the brake with my right foot; i.e., the loop prevented me from placing my right foot on top of the brake pedal.

You can only imagine the ensuing period of panic as I tried to push the brake pedal. My left foot, which normally only works the clutch, tried to help as best it could. After all the chaotic pumping and flailing with both feet, my right foot was finally freed up; I then applied the brake with my right foot and the clutch with my left foot, as usual.

For a while after that incident, I double-knotted my sneakers to reduce the size of the loops. I haven't done that in a while but I should.

This discussion reminds me of a comment my father-in-law made concerning bridge design. He was pondering whether a particular bridge was (1) designed by a Civil Engineer who studied constantly, didn't party, made good grades, then registered as a PE, and spent sleepless nights wondering if he had considered all possible stressors and failure scenarios for the design of his bridge or (2) one who partied in college, got by in his grades, sucked on the boss at his new job, was very articulate and made great presentations to management, delegated all the details to others, got all the promotions and eventually rose to the top of the corporate ladder. He concluded that he hoped each bridge he drove across was designed by engineer #1, not engineer #2.

What i disliked the most was the publicity that toyotas recalls got when at the same time chevi recalls got no publicity. I have two impalas and a carolla. The impallas had a total of 5 recalls last 2 years the carola had 1 recall. Impallas had problems with the seats comming lose, the seatbelt chocking u in an accident and several others. The carolas computer was having delamination of the pcb trace. This was blamed for excessive acceleration.

No, not only was the truck brand new it was checked by the dealer after the first episode. I began to wonder if I was the only one so I posted the story on a Ford truck owners forum. There were several replys from others who had experienced the same problem. I haven't had any problems since because I'm aware of it and consciously make an effort to place my foot squarely on the brake pedal. Unfortunately that may not always be reliable in a panic situation.

Industrial workplaces are governed by OSHA rules, but this isn’t to say that rules are always followed. While injuries happen on production floors for a variety of reasons, of the top 10 OSHA rules that are most often ignored in industrial settings, two directly involve machine design: lockout/tagout procedures (LO/TO) and machine guarding.

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